[Mammoth] Add a user-space semaphore object.

lib/mammoth/CMakeLists.txt

@@ -10,6 +10,7 @@ add_library(mammoth STATIC
   src/process.cpp
   src/port_client.cpp
   src/port_server.cpp
+  src/semaphore.cpp
   src/thread.cpp
   )
 

lib/mammoth/include/mammoth/semaphore.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <ztypes.h>
+
+class Semaphore {
+ public:
+  Semaphore();
+  ~Semaphore();
+
+  void Wait();
+  void Signal();
+
+ private:
+  z_cap_t semaphore_cap_;
+};

lib/mammoth/src/semaphore.cpp

@@ -0,0 +1,11 @@
+#include "mammoth/semaphore.h"
+
+#include <zcall.h>
+
+#include "mammoth/debug.h"
+
+Semaphore::Semaphore() { check(ZSemaphoreCreate(&semaphore_cap_)); }
+Semaphore::~Semaphore() { check(ZCapRelease(semaphore_cap_)); }
+
+void Semaphore::Wait() { check(ZSemaphoreWait(semaphore_cap_)); }
+void Semaphore::Signal() { check(ZSemaphoreSignal(semaphore_cap_)); }